(1) Field of the Invention
The present invention relates to an electric rotary machine in which a magnetic circuit (or a magnetic path) is formed between a rotor and a stator, and, more specifically, relates to a technique in the electric rotary machine which prevents a reduction of a driving efficiency generated due to an overflow of the magnetic path from a naturally ideal position of the magnetic path.
(2) Description of the Related Art
An electric machine in which a stator in which coil windings are equipped is supported by means of a metallic supporting member is exemplified by a Japanese Patent Application Publication (tokouhyou) of PCT Application (whose international publication is WO 03/084027) No. 2005-522166 published on Jul. 21, 2005 which corresponds to a U.S. Pat. No. 6,765,327 issued on Jul. 20, 2004.
The previously proposed electric rotary machine disclosed in the above-described Japanese Patent Application Publication houses a rotor and the stator in an internal spatial region of a case made of an aluminum alloy. Cooling fins are attached on an external of the case. The stator is attached in an inside of the case. The stator is laminated with a plurality of thin-plate steel plates and non electrically conductive nonferrous layers. The stator minimizes a loss due to an eddy current of a magnetic flux at the inside of the stator. Furthermore, the stator is partitioned by means of thirty-six (36) grooves in a peripheral direction of the stator. The stator has the same number of stator cores as that of the grooves. An electrically conductive coil winding is wound on each of the stator cores. Since the case described above is formed of the aluminum alloy having a high thermal conductivity, heat generated on the coil windings and stator cores can speedily be discharged through the external of the case while a rigidity of the electric rotary machine is secured. Thus, a cooling performance of the electric rotary machine described above becomes high.